/*
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 * NominalToString.java
 * Copyright (C) 2007-2012 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.filters.unsupervised.attribute;

import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Vector;

import weka.core.Attribute;
import weka.core.Capabilities;
import weka.core.Capabilities.Capability;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.Option;
import weka.core.OptionHandler;
import weka.core.Range;
import weka.core.UnsupportedAttributeTypeException;
import weka.core.Utils;
import weka.core.WeightedAttributesHandler;
import weka.core.WeightedInstancesHandler;
import weka.filters.Filter;
import weka.filters.UnsupervisedFilter;

/**
 * <!-- globalinfo-start --> Converts a nominal attribute (i.e. set number of
 * values) to string (i.e. unspecified number of values).
 * <p/>
 * <!-- globalinfo-end -->
 * 
 * <!-- options-start --> Valid options are:
 * <p/>
 * 
 * <pre>
 * -C &lt;col&gt;
 *  Sets the range of attributes to convert (default last).
 * </pre>
 * 
 * <!-- options-end -->
 * 
 * @author FracPete (fracpete at waikato dot ac dot nz)
 * @version $Revision$
 */
public class NominalToString extends Filter implements UnsupervisedFilter, OptionHandler, WeightedInstancesHandler, WeightedAttributesHandler {

    /** for serialization */
    static final long serialVersionUID = 8655492378380068939L;

    /** The attribute's index setting. */
    private final Range m_AttIndex = new Range("last");

    /**
     * Returns a string describing this filter
     * 
     * @return a description of the filter suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String globalInfo() {
        return "Converts a nominal attribute (that is, a set number of values) to string " + "(that is, an unspecified number of values).";
    }

    /**
     * Returns the Capabilities of this filter.
     * 
     * @return the capabilities of this object
     * @see Capabilities
     */
    @Override
    public Capabilities getCapabilities() {
        Capabilities result = super.getCapabilities();
        result.disableAll();

        // attributes
        result.enableAllAttributes();
        result.enable(Capability.MISSING_VALUES);

        // class
        result.enableAllClasses();
        result.enable(Capability.MISSING_CLASS_VALUES);
        result.enable(Capability.NO_CLASS);

        return result;
    }

    /**
     * Sets the format of the input instances.
     * 
     * @param instanceInfo an Instances object containing the input instance
     *                     structure (any instances contained in the object are
     *                     ignored - only the structure is required).
     * @return true if the outputFormat may be collected immediately.
     * @throws UnsupportedAttributeTypeException if the selected attribute a string
     *                                           attribute.
     * @throws Exception                         if the input format can't be set
     *                                           successfully.
     */
    @Override
    public boolean setInputFormat(Instances instanceInfo) throws Exception {
        super.setInputFormat(instanceInfo);

        m_AttIndex.setUpper(instanceInfo.numAttributes() - 1);

        /*
         * if (!instanceInfo.attribute(m_AttIndex.getIndex()).isNominal()) throw new
         * UnsupportedAttributeTypeException("Chosen attribute is not of " +
         * "type nominal.");
         */

        return false;
    }

    /**
     * Input an instance for filtering. The instance is processed and made available
     * for output immediately.
     * 
     * @param instance the input instance.
     * @return true if the filtered instance may now be collected with output().
     * @throws IllegalStateException if no input structure has been defined.
     */
    @Override
    public boolean input(Instance instance) {
        if (getInputFormat() == null) {
            throw new IllegalStateException("No input instance format defined");
        }

        if (m_NewBatch) {
            resetQueue();
            m_NewBatch = false;
        }

        if (isOutputFormatDefined()) {
            Instance newInstance = (Instance) instance.copy();
            push(newInstance, false); // No need to copy
            return true;
        }

        bufferInput(instance);
        return false;
    }

    /**
     * Signifies that this batch of input to the filter is finished. If the filter
     * requires all instances prior to filtering, output() may now be called to
     * retrieve the filtered instances.
     * 
     * @return true if there are instances pending output.
     * @throws IllegalStateException if no input structure has been defined.
     */
    @Override
    public boolean batchFinished() {
        if (getInputFormat() == null) {
            throw new IllegalStateException("No input instance format defined");
        }

        if (!isOutputFormatDefined()) {
            setOutputFormat();

            // Convert pending input instances
            for (int i = 0; i < getInputFormat().numInstances(); i++) {
                push((Instance) getInputFormat().instance(i).copy(), false); // No need to copy
            }
        }

        flushInput();
        m_NewBatch = true;

        return (numPendingOutput() != 0);
    }

    /**
     * Returns an enumeration describing the available options.
     * 
     * @return an enumeration of all the available options.
     */
    @Override
    public Enumeration<Option> listOptions() {

        Vector<Option> result = new Vector<Option>();

        result.addElement(new Option("\tSets the range of attributes to convert (default last).", "C", 1, "-C <col>"));

        return result.elements();
    }

    /**
     * Parses a given list of options.
     * <p/>
     * 
     * <!-- options-start --> Valid options are:
     * <p/>
     * 
     * <pre>
     * -C &lt;col&gt;
     *  Sets the range of attributes to convert (default last).
     * </pre>
     * 
     * <!-- options-end -->
     * 
     * @param options the list of options as an array of strings
     * @throws Exception if an option is not supported
     */
    @Override
    public void setOptions(String[] options) throws Exception {

        String tmpStr = Utils.getOption('C', options);
        if (tmpStr.length() != 0) {
            setAttributeIndexes(tmpStr);
        } else {
            setAttributeIndexes("last");
        }

        if (getInputFormat() != null) {
            setInputFormat(getInputFormat());
        }

        Utils.checkForRemainingOptions(options);
    }

    /**
     * Gets the current settings of the filter.
     * 
     * @return an array of strings suitable for passing to setOptions
     */
    @Override
    public String[] getOptions() {

        Vector<String> result = new Vector<String>();

        result.add("-C");
        result.add("" + (getAttributeIndexes()));

        return result.toArray(new String[result.size()]);
    }

    /**
     * Returns the tip text for this property
     * 
     * @return tip text for this property suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String attributeIndexesTipText() {
        return "Sets a range attributes to process. Any non-nominal " + "attributes in the range are left untouched (\"first\" and \"last\" are valid values)";
    }

    /**
     * Get the index of the attribute used.
     * 
     * @return the index of the attribute
     */
    public String getAttributeIndexes() {
        // return m_AttIndex.getSingleIndex();
        return m_AttIndex.getRanges();
    }

    /**
     * Sets index of the attribute used.
     * 
     * @param attIndex the index of the attribute
     */
    public void setAttributeIndexes(String attIndex) {
        // m_AttIndex.setSingleIndex(attIndex);
        m_AttIndex.setRanges(attIndex);
    }

    /**
     * Set the output format. Takes the current average class values and
     * m_InputFormat and calls setOutputFormat(Instances) appropriately.
     */
    private void setOutputFormat() {
        Instances newData;
        ArrayList<Attribute> newAtts = new ArrayList<Attribute>(getInputFormat().numAttributes());
        for (int j = 0; j < getInputFormat().numAttributes(); j++) {
            Attribute att = getInputFormat().attribute(j);

            if (!att.isNominal() || !m_AttIndex.isInRange(j)) {
                newAtts.add(att);
            } else {
                Attribute newAtt = new Attribute(att.name(), (ArrayList<String>) null);
                newAtt.setWeight(getInputFormat().attribute(j).weight());
                newAtts.add(newAtt);
            }
        }

        // Construct new header
        newData = new Instances(getInputFormat().relationName(), newAtts, 0);
        newData.setClassIndex(getInputFormat().classIndex());

        setOutputFormat(newData);
    }

    /**
     * Main method for testing this class.
     * 
     * @param args should contain arguments to the filter: use -h for help
     */
    public static void main(String[] args) {
        runFilter(new NominalToString(), args);
    }
}
